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FFCobra Craftsman
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Discussion Starter #1
My car, stock '88 Mustang EFI, suddenly developed a severe miss on all cylinders. All the plugs are wet with gas. That points to something from the coil to the distributer cap, doesn't it? Coil, coil wire, or distributor button/cap/rotor? Distributor button/cap/rotor are new and look OK. Coil wire is new. Coil is the original off of the donor mustang.
What kind of diagnosis can I do to try to pinpoint the missing? Just shotgun it and start with a new coil?
This type of problem isn't typical of a TFI module is it? From what other guys have written, the TFI module either works or doesn't, correct?
Thanks for any diagnostic insight,

[ September 12, 2005, 12:49 AM: Message edited by: lperry, #4227 ]
 

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lperry,

There are 2 modules on a Ford distributor. The outer one (TFI) and an inner one that managed the Hall Effect sensor that is the trigger for the TFI. There is a magnet on the inner module that can come loose (it happened to me on 4402) and will cause very weird problems including a dead motor. Take the cap and rotor off and look to see that the magnet is still held in it’s original position.

Check the internal resistance of the coil wire to be sure that it is not burned out internally, I had this also.

Check that resistances of the two windings of your ignition coil, with a volt/ohm meter, are correct. If not replace it

Check the harness from the TFI to the computer with a volt/ohm meter. Be sure that you have continuity on all the wires

Check the resistance values for the TFI with a volt/ohm meter; if not correct replace it…

Some places to look first… good luck.

Chris
 

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FFCobra Craftsman
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Discussion Starter #5
Am checking Chris' suggestions and trying to borrow a fuel pressure gauge to check that.
I'll also check codes. It's running too bad to get KOER but I'll look at the KOEO codes and see if they tell me anything.
Thanks for the ideas,
 

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lperry,

I should have also told you to do the spark-gap test. Take the dist end of the coil wire and lay it about 1/2 inch from any metal that is grounded and won't start a fire. If you see a "thick" blue spark and it makes a good "wack" sound, it's not the ignition... If the spark is yellow you may have a weak link in the ignition system. If there is no spark keep going with my list...

BTW, DONT HOLD THE COIL WIRE DURING THE TEST, lay it on the metal and just turn the key and watch... :eek:

Just wanted to shorten the "pain" a little...

Chris
 

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Larry - I think your problem is fuel injection / ECU related. Double-check the grounding of the ECU and harness. Make sure you disconnect the battery, then disconnect the ECU and reconnect (to re-seat the connector) then re-connect the battery.

If that doesn't help, I would see if you could borrow another ECU and try it.

If this started suddenly - it's almost certain that it is electrical...
 
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